RCD UnionfiningTM Process

Refining

Refining
The UOP RCD Unionfining process is a fixed-bed Figure 1 RCD Unionfining Process
catalytic residue hydrotreating technology that
reduces the contaminants in heavy feedstocks, Fixed Bed Reactors

such as atmospheric residue, vacuum residue, and

Residue
deasphalted oil (DAO). Feed Feed
Filters Hot
Separator

Currently, the most common application of the RCD

Unionfining process is FCC/RFCC feed pretreatment, H2
Makeup
in which approximately 90% of the sulfur and organo-
Fractionator
metallics are removed. The process is also used for H2
Recovery Gas

production of low sulfur fuel oil and partial conversion Purge Naphtha
To Fuel Gas
of non-distillables in the feed to distillables. Cold
Distillate
H2S Separator
Scrubber Hot
Cold
Flash Flash
Process Description Hydrotreated
Residue

The RCD Unionfining process is a fixed-bed hydro-

genation process that uses base metal catalysts to
remove contaminants, such as sulfur, nitrogen, Impact of Feedstock Quality and Processing
organometallics, and asphaltenes, and to increase Objectives
the hydrogen content of the products.
The ease of processing a feedstock depends on the
The feedstock is first filtered before combining with nature of the asphaltenic molecule and the distribu-
hydrogen and passing through the catalyst beds at tion of contaminants throughout the resin and
elevated temperatures and low space velocities. asphaltene fractions. Relative processing severity is
Because of the typical high contaminant levels, a dependent on feedstock type and processing objec-
guard bed reactor is used to control pressure drop tives (Figure 2). Consequently, the process operates
associated with large particles and solids that may over a large range of operating conditions: 1,500-
be in the residue feed. Often several reactors in 3,000 psi and 0.10-1.0 LHSV. Feedstocks with high
series are required because of the relatively low contaminants, such as vacuum residues, typically
reactivities of the feedstocks. have higher pressures and lower space velocities.

The reactor effluent, which contains the products,

recycle gas, and by-products, is then separated into Figure 2 Required Processing Severity
the desired products through a combination of vs. Feedstock Type
separators, flash stages, and eventually, fractionation
equipment. The hydrogen recycle gas requires Vacuum
Resid
scrubbing to remove H2S. Then it is combined with
makeup gas before being recycled to the reactors
Δ AR

(Figure 1). Atmospheric

Catalyst Volume

Resid
Pressure

Good flow distribution in a trickle-bed resid hydro-

DAO

treater reactor is critical to both performance and DAO

safety. Poor flow distribution can result in an uneven
temperature rise in the reactor, which can ultimately VGO
lead to shorter catalyst life, hot spots, and product
instability. Desulfurization
RCD Unionfining Process 2

Catalyst Selection and Loading Temperature is the normal control variable. As

It is essential to tailor catalyst selection to processing catalyst activity declines over the cycle, temperature
objectives and feedstock quality. There are two is adjusted to maintain catalytic activity. This
major concerns: increases the conversion level of residues to distillates.
Some operators may allow the process performance
 Pressure drop build-up across the front-end to decline over the cycle, accepting higher product
reactor sulfur and metals content as a tradeoff to increased
 Optimum process performance in terms of conversion.
desulfurization and demetallization
Experience
Consequently, the selection of catalysts is complex
RCD Unionfining technological services are available
in the RCD Unionfining process. Typically, several
on request. UOP has designed and licensed 27 RCD
types of catalysts, which have different functions
Unionfining process units, ranging in size from 7,000
and relative activities, are utilized to meet the
to 75,000 BPD.
process objectives (Figure 3).

UOP offers a wide choice of catalysts tailored to For More Information

meet the customer’s precise needs. These include RCD Unionfining technological services are
catalyst formulations developed by UOP and available on request. For more information, contact
Albemarle. your local UOP representative or contact our
Des Plaines sales office:
Figure 3 Typical Catalyst Loading
e-mail: info@uop.com
fax: +1-847-391-2253
phone: +1-847-391-2000

= Non Plugging
Type
= HDM Type
= HDS Type

UOP LLC
25 East Algonquin Road
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Des Plaines, IL 60017-5017 The information in this document should not be construed as a representation for
which UOP assumes legal responsibility, or an authorization or recommendation
U.S.A. to practice a patented invention without a license.
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